Alexander Kiss

The effect of tracheostomy timing during critical illness on long-term survival*

Background:Tracheostomy is common in intensive care unit patients, but the appropriate timing is controversial. Objective:To determine whether earlier tracheostomy is associated with greater long-term survival. Design:Retrospective cohort analysis. Setting:Acute care hospitals in Ontario, Canada (n = 114). Patients:All mechanically ventilated intensive care unit patients who received tracheostomy between April 1, 1992 and March 31, 2004, excluding extreme cases (<2 or ≥28 days) and children (<18 yrs). Measurements:For crude analyses, tracheostomy timing was classified as early (≤10 days) vs. late (>10 days) with mortality measured at multiple follow-up intervals. Proportional hazards analyses considered tracheostomy as a time-dependent variable to adjust for measurable confounders and possible survivor treatment bias. We used stratification, propensity score, and instrumental variable analyses to adjust for patient differences. Results:A total of 10,927 patients received tracheostomy during the study, of which one-third (n = 3758) received early and two-thirds late (n = 7169). Patients receiving early tracheostomy had lower unadjusted 90-day (34.8% vs. 36.9%; p = 0.032), 1 yr (46.5% vs. 49.8%; p = 0.001), and study mortality (63.9% vs. 67.2%; p < 0.001) than patients receiving late tracheostomy. Multivariable analyses treating tracheostomy as a time-dependent variable showed that each additional delay of 1 day was associated with increased mortality (hazard ratio 1.008, 95% confidence interval 1.004–1.012), equivalent to an increase in 90-day mortality from 36.2% to 37.6% per week of delay (relative risk increase 3.9%; number needed to treat, 71 patients to save one life per week delay). Limitations:This analysis provides guidance regarding timing but not patient selection for tracheostomy. Conclusions:Physicians performing early tracheostomy should not anticipate a large potential survival benefit. Future research should concentrate on identifying which patients will receive the most benefit.

In Vivo 3D High-Spatial-Resolution MR Imaging of Intraplaque Hemorrhage

PURPOSEnTo apply magnetic resonance (MR) imaging of intraplaque hemorrhage (IPH), as compared with histologic analysis as the reference standard, to detect T1 hyperintense intraplaque signal and to test the hypothesis that T1 hyperintense material represents blood products (methemoglobin).nnnMATERIALS AND METHODSnInstitutional review board approval and patient informed consent were obtained. Eleven patients undergoing carotid endarterectomy were examined with MR imaging of IPH, and MR images were assessed for T1 hyperintense intraplaque signal. A total of 160 images per patient were available for coregistration with corresponding histologic slices. Because of endarterectomy specimen size and degradation and processing artifacts, only 97 images were coregistered to corresponding histologic slices. A grid that consisted of 16 segments was overlaid on images for correlation of MR images and histologic slices. Only one of 16 segments was chosen randomly per slide and used in the analysis. Agreement between MR images and histologic slices was measured with the Cohen kappa statistic.nnnRESULTSnStrong agreement was seen between MR images and histologic slices, with T1-weighted high signal intensity corresponding to hemorrhagic material (kappa = 0.7-0.8). There was a low 2% false-negative rate for the detection of hemorrhage on the basis of T1-weighted hyperintensity (two of 97 measured segments). The results of diagnostic tests for T1 hyperintense detection of hemorrhage were as follows: sensitivity of 100%, specificity of 80%, positive predictive value of 70%, and negative predictive value of 100% for reader 1 and sensitivity of 94%, specificity of 88%, positive predictive value of 78%, and negative predictive value of 97% for reader 2.nnnCONCLUSIONnWith its high spatial resolution, MR imaging of IPH permits detection of plaque hemorrhage location, resulting in strong agreement between imaging and histologic findings.

Intracranial pressure monitoring in severe traumatic brain injury: results from the American College of Surgeons Trauma Quality Improvement Program.

Although existing guidelines support the utilization of intracranial pressure (ICP) monitoring in patients with traumatic brain injury (TBI), the evidence suggesting benefit is limited. To evaluate the impact on outcome, we determined the relationship between ICP monitoring and mortality in centers participating in the American College of Surgeons Trauma Quality Improvement Program (TQIP). Data on 10,628 adults with severe TBI were derived from 155 TQIP centers over 2009-2011. Random-intercept multilevel modeling was used to evaluate the association between ICP monitoring and mortality after adjusting for important confounders. We evaluated this relationship at the patient level and at the institutional level. Overall mortality (n=3769) was 35%. Only 1874 (17.6%) patients underwent ICP monitoring, with a mortality of 32%. The adjusted odds ratio (OR) for mortality was 0.44 [95% confidence interval (CI), 0.31-0.63], when comparing patients with ICP monitoring to those without. It is plausible that patients receiving ICP monitoring were selected because of an anticipated favorable outcome. To overcome this limitation, we stratified hospitals into quartiles based on ICP monitoring utilization. Hospitals with higher rates of ICP monitoring use were associated with lower mortality: The adjusted OR of death was 0.52 (95% CI, 0.35-0.78) in the quartile of hospitals with highest use, compared to the lowest. ICP monitoring utilization rates explained only 9.9% of variation in mortality across centers. Results were comparable irrespective of the method of case-mix adjustment. In this observational study, ICP monitoring utilization was associated with lower mortality. However, variability in ICP monitoring rates contributed only modestly to variability in institutional mortality rates. Identifying other institutional practices that impact on mortality is an important area for future research.

A Clinical Prediction Model for Long-Term Functional Outcome after Traumatic Spinal Cord Injury Based on Acute Clinical and Imaging Factors

To improve clinicians ability to predict outcome after spinal cord injury (SCI) and to help classify patients within clinical trials, we have created a novel prediction model relating acute clinical and imaging information to functional outcome at 1 year. Data were obtained from two large prospective SCI datasets. Functional independence measure (FIM) motor score at 1 year follow-up was the primary outcome, and functional independence (score ≥ 6 for each FIM motor item) was the secondary outcome. A linear regression model was created with the primary outcome modeled relative to clinical and imaging predictors obtained within 3 days of injury. A logistic model was then created using the dichotomized secondary outcome and the same predictor variables. Model validation was performed using a bootstrap resampling procedure. Of 729 patients, 376 met the inclusion criteria. The mean FIM motor score at 1 year was 62.9 (±28.6). Better functional status was predicted by less severe initial American Spinal Injury Association (ASIA) Impairment Scale grade, and by an ASIA motor score >50 at admission. In contrast, older age and magnetic resonance imaging (MRI) signal characteristics consistent with spinal cord edema or hemorrhage predicted worse functional outcome. The linear model predicting FIM motor score demonstrated an R-square of 0.52 in the original dataset, and 0.52 (95% CI 0.52,0.53) across the 200 bootstraps. Functional independence was achieved by 148 patients (39.4%). For the logistic model, the area under the curve was 0.93 in the original dataset, and 0.92 (95% CI 0.92,0.93) across the bootstraps, indicating excellent predictive discrimination. These models will have important clinical impact to guide decision making and to counsel patients and families.

Intensive care outcomes in bone marrow transplant recipients: a population-based cohort analysis

IntroductionIntensive care unit (ICU) admission for bone marrow transplant recipients immediately following transplantation is an ominous event, yet the survival of these patients with subsequent ICU admissions is unknown. Our objective was to determine the long-term outcome of bone marrow transplant recipients admitted to an ICU during subsequent hospitalizations.MethodsWe conducted a population-based cohort analysis of all adult bone marrow transplant recipients who received subsequent ICU care in Ontario, Canada from 1 January 1992 to 31 March 2002. The primary endpoint was mortality at 1 year.ResultsA total of 2,653 patients received bone marrow transplantation; 504 of which received ICU care during a subsequent hospitalization. Patients receiving any major procedure during their ICU stay had higher 1-year mortality than those patients who received no ICU procedure (87% versus 44%, P < 0.0001). Death rates at 1 year were highest for those receiving mechanical ventilation (87%), pulmonary artery catheterization (91%), or hemodialysis (94%). In combination, the strongest independent predictors of death at 1 year were mechanical ventilation (odds ratio, 7.4; 95% confidence interval, 4.8 to 11.4) and hemodialysis (odds ratio, 8.7; 95% confidence interval, 2.1 to 36.7), yet no combination of procedures uniformly predicted 100% mortality.ConclusionThe prognosis of bone marrow transplant recipients receiving ICU care during subsequent hospitalizations is very poor but should not be considered futile.

Morbidity in Patients with or at High Risk for Obstructive Sleep Apnea after Ambulatory Laparoscopic Gastric Banding

Considerable controversy exists about the perioperative management of patients at high risk for obstructive sleep apnea (OSA) in free-standing clinics. Eighty-eight percent of an American Society of Anesthesiologists expert panel felt that upper abdominal laparoscopic surgery could not be performed safely on an outpatient basis. We sought to review the incidence of major adverse events after outpatient laparoscopic adjustable gastric banding (LAGB) in a high risk population for OSA at a free-standing facility. Research Ethics Board approval was obtained and charts were reviewed retrospectively for 2,370 LAGB performed at a free-standing clinic between 2005 and 2009. In this observational cohort study, patients were classified as high risk for OSA if they received continuous positive airway pressure (CPAP) treatment for OSA pre-operatively or had a history of at least three STOP-BANG criteria. Follow-up was verified and adverse events reviewed, including death, unanticipated transfer or admission to hospital within 30xa0days. A total of 746 of the 2,370 patients (31%) met criteria for or were at high risk for OSA (357 received CPAP for OSA and 389 by STOP-BANG criteria). The incidence of transient desaturation to less than 93% was 39.5%. There were no deaths and no cases of respiratory failure or re-intubation. The 30-day mortality was zero and the 30-day anesthesia related morbidity was less than 0.5%. For patients at high risk for OSA after LAGB, the significance of transient oxygen desaturation and the need to develop monitoring and admission standards remain to be determined.

Identifying a high risk cardiovascular phenotype by carotid MRI-depicted intraplaque hemorrhage

Intraplaque hemorrhage (IPH), a component of late-stage complicated plaque, identified within carotid endarterectomy surgical specimens has been recently demonstrated to predict cardiovascular (CV) events. MRI is able to depict carotid IPH. We investigated the ability of carotid MR-depicted IPH (MR-IPH) to identify high-risk CV patients. From January 2008 to April 2011, 216 patients (mean age, 67.5xa0years; range 31–100) referred for neurovascular MRI at an academic tertiary care centre, underwent 3T carotid MRI with adjunct 3D high-spatial-resolution coronal imaging to detect MR-IPH. Five experienced neuroradiologists made a binary decision on the presence or absence of MR-IPH. Patients’ charts were reviewed blindly for demographic and CV outcomes data. Of the patients with and without MR-IPH, 62.5xa0% (15/24) and 19.8xa0% (38/192) had a composite CV event (defined as a past myocardial infarction, coronary intervention (i.e., angioplasty, stenting or bypass graft) and/or peripheral vascular disease), respectively. The odds ratio (OR) of a composite CV event in the MR-IPH group was 6.75 (Bivariable analysis, 95xa0% CI 2.75–16.6, pxa0<xa00.0001) and 3.25 (Multivariable regression analysis, 1.14–9.37, pxa0=xa00.028). MR-IPH had the highest OR of a prior CV event compared to other variables including age, sex, hypertension and stenosis. The OR of individual CV events was also significant: MI (3.35, 95xa0% CI 2.11–14.2, pxa0<xa00.01), coronary stenting (26.4, 95xa0% CI 8.80–79.4, pxa0<xa00.01), coronary angioplasty (21, 95xa0% CI 4.84–91.1, pxa0<xa00.01), and PVD (3.35, 95xa0% CI 1.09–10.3, pxa0<xa00.05). MR-IPH is independently associated with prior CV events in patients who are evaluated for neurovascular disease. Carotid MR-IPH, employed easily in routine clinical practice, is emerging as an indicator of systemic vascular disease and may potentially be a useful surrogate marker of CV risk including in those already undergoing neurovascular imaging.

In Vivo Identification of Complicated Upper Thoracic Aorta and Arch Vessel Plaque by MR Direct Thrombus Imaging in Patients Investigated for Cerebrovascular Disease

OBJECTIVEnThe objective of this article was to assess the feasibility of MR direct thrombus imaging (MRDTI) to evaluate the prevalence and location of complicated upper thoracic aortic and arch vessel plaque in patients referred for evaluation of cerebrovascular disease.nnnSUBJECTS AND METHODSnPatients referred for investigation of cerebrovascular disease by MRI were enrolled. Reasons for referral included transient ischemic attack/amaurosis fugax, acute infarct, remote infarct, or asymptomatic carotid disease. Of the 348 patients initially scanned, 17 were excluded from the analysis. The final patient population included 331 patients (199 men, 132 women; mean age, 67.7 years). Patients were scanned using MRDTI, a 3D, T1-weighted, fat-suppressed spoiled gradient echo that exploits the T1 shortening effects of methemoglobin, directly visualizing hemorrhage/thrombus in the vessel wall, thus identifying complicated plaque. Complicated plaque was defined as a high signal within the atherosclerotic plaque at least twice the signal intensity of muscle.nnnRESULTSnForty-three of 331 patients (13%) had complicated upper thoracic aortic atherosclerotic disease, arch vessel atherosclerotic disease, or both. The upper thoracic aorta was involved in 36 of 43 patients (83.7%), and the left subclavian artery was involved in 14 of 43 patients (32.6%). Both the right subclavian artery and the brachiocephalic artery were involved in one of 43 patients (2.3%). Complicated carotid plaque was seen in 25 of 43 patients (58.1%).nnnCONCLUSIONnMRDTI can be applied in the detection of complicated plaque in the upper thoracic aorta and arch vessels. Complicated plaque was identified in 13% of the patient population. The upper thoracic aorta was the most common site involved. This technique could be useful for the screening of asymptomatic at-risk patients.

Targeted temperature management processes and outcomes after out-of-hospital cardiac arrest: an observational cohort study*.

Objectives:Targeted temperature management has been shown to improve survival with good neurological outcome in patients after out-of-hospital cardiac arrest. The optimal approach to inducing and maintaining targeted temperature management, however, remains uncertain. The objective of this study was to evaluate these processes of care with survival and neurological function in patients after out-of-hospital cardiac arrest. Design:An observational cohort study evaluating the association of targeted temperature management processes with survival and neurological function using bivariate and generalized estimating equation analyses. Setting:Thirty-two tertiary and community hospitals in eight urban and rural regions of southern Ontario, Canada. Patients:Consecutive adult (≥ 18 yr) patients admitted between November 1, 2007, and January 31, 2012, and who were treated with targeted temperature management following nontraumatic out-of-hospital cardiac arrest. Interventions:Evaluate the association of targeted temperature management processes with survival and neurologic function using bivariate and generalized estimating equation analyses. Measurements and Main Results:There were 5,770 consecutive out-of-hospital cardiac arrest patients, of whom 747 (12.9%) were eligible and received targeted temperature management. Among patients with available outcome data, 365 of 738 (49.5%) survived to hospital discharge and 241 of 675 (35.7%) had good neurological outcomes. After adjusting for the Utstein variables, a higher temperature prior to initiation of targeted temperature management was associated with improved neurological outcomes (odds ratio, 1.27 per °C; 95% CI, 1.08–1.50; p = 0.004) and survival (odds ratio, 1.26 per °C; 95% CI, 1.09–1.46; p = 0.002). A slower rate of cooling was associated with improved neurological outcomes (odds ratio, 0.74 per °C/hr; 95% CI, 0.57–0.97; p = 0.03) and survival (odds ratio, 0.73 per °C/hr; 95% CI, 0.54–1.00; p = 0.049). Conclusions:A higher baseline temperature prior to initiation of targeted temperature management and a slower rate of cooling were associated with improved survival and neurological outcomes. This may reflect a complex relationship between the approach to targeted temperature management and the extent of underlying brain injury causing impaired thermoregulation in out-of-hospital cardiac arrest patients.

Beyond the dollar: Influence of sociodemographic marginalization on surgical resection, adjuvant therapy, and survival in patients with pancreatic cancer.

The single‐payer universal health care system in Ontario, Canada creates a setting with reduced socioeconomic barriers to treatment. Herein, the authors sought to elucidate the influence of sociodemographic marginalization on receipt of pancreatectomy, overall survival (OS), and receipt of adjuvant treatment among patients diagnosed with pancreatic cancer at the population level using an observational cohort study design.